The present invention relates to a tunable antenna having separate radiator parts for tuning to a desired radiation pattern and to a process for manufacturing the antenna.
In the prior art, the molded interconnect device (xe2x80x9cMIDxe2x80x9d) technology discloses, among other things, that it is possible to manufacture inexpensive antennas for, i.e., mobile telephones or the like. More precisely, a structure capable of radiating or conducting such as, for example, a helix is galvanically applied to a carrier that is generally round.
Antennas manufactured in such a way are generally narrow-band antennas. Accordingly, it is necessary to tune these antennas to a desired resonant frequency. Such tuning or readjustment has previously been achieved by determining the radiator length of the antenna.
During manufacture of the above-mentioned antennas, however, unavoidable, slight variations in tolerance are obtained. As a result of the variations in tolerance, the respective resonant frequencies of the individual antennas are not at a stable value but change in accordance with the systematic variations in tolerance existing in the antennas during the manufacture of these antennas. The consequence is that the resonant frequencies of the various antennas manufactured by the same process change towards higher or lower values during the manufacturing process. The effect has a permanent negative effect on the quality of the various antennas.
In prior art manufacturing processes, the only possibility for compensating for such variations in tolerance lies in readjusting the antennas by changing the length of the radiators; meaning that it is necessary to make changes in or on the tool used itself. However, such changes are extremely complex and very expensive. A further decisive disadvantage of the prior art manufacturing processes also exists in that such changes in or on the tool can always only be carried out for large numbers but not for relatively small numbers or even individual antennas. As a result, it is not possible to compensate for short-term variations in tolerance occurring generally.
It is accordingly an object of the invention to provide a tunable antenna having separate radiator parts for tuning to a desired radiation pattern and a process for manufacturing the antenna that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that can be tuned to a desired radiation pattern with little manufacturing expenditure
With the foregoing and other objects in view, there is provided, in accordance with the invention, a tunable antenna, including at least first and second separate radiator parts having a couple therebetween and defining a radiation pattern, the couple formed to be changed by at least one of rotation and displacement of the at least first and second radiator parts with respect to one another where a respective degree of at least one of rotation and displacement creates a corresponding change the radiation pattern.
According to the invention, a tunable antenna is created that has at least first and second separately constructed radiator parts that are coupled to one another. Coupling between the radiator parts can be changed by rotating and/or displacing the radiator parts with respect to one another such that the antenna exhibits a radiation pattern associated with a respective degree of a rotation and/or displacement.
Accordingly, the antenna of the invention achieves an essential advantage that the antenna can be changed in a simple manner in its effective radiator length by a rotation and/or displacement of the radiator parts. Because the radiation pattern of the antenna is a function of the effective radiator length, the radiation pattern of the antenna can also be changed in a simple manner by rotating and/or displacing the radiator parts with respect to one another. The resonant frequency or, respectively, the resonant frequencies of the antenna represent a measure of the effective radiator length and can be used for assessing the radiation pattern.
The coupling between the radiator parts can be an electrical coupling, a capacitive coupling, and/or an inductive coupling.
In accordance with another feature of the invention, there is provided a cap for covering the separate radiator parts.
In accordance with a further feature of the invention, the first radiator part has a first helix and a conductor part. The first helix has an end, a first longitudinal center axis and extends parallel or inclined to the first longitudinal center axis. The conductor part is disposed at the end. The second radiator part has a second helix and an open turn. The second helix has an end and a second longitudinal center axis. The open turn is disposed at the end and is disposed in a plane extending one of perpendicularly and inclined to the second longitudinal center axis of the helix.
In accordance with an added feature of the invention, the radiator parts are disposed with respect to one another to align the longitudinal center axes of the helices and such that the conductor part electrically contacts the open turn. At least one of the radiator parts is formed to rotate about a respective longitudinal center axis of the helix.
In accordance with an additional feature of the invention, the radiator parts are a plurality of first and second radiator parts disposed in an alternating sequence.
In accordance with yet another feature of the invention, there is provided a third radiator part having a rod, a conductor part, and an open turn. The rod has a longitudinal center axis and first and second ends. The conductor part is disposed at the first end and has a longitudinal center axis aligned with the longitudinal center axis of the rod. The open turn is disposed at the second end and is located in a plane extending perpendicular or inclined to the longitudinal center axis of the rod.
In accordance with yet a further feature of the invention, the radiator parts are disposed with respect to one another such that the longitudinal center axes of the helices of first and second radiator parts are aligned. The longitudinal center axes of the rod and of the conductor part of a third radiator part extend one of parallel and inclined to the longitudinal center axes of the helices of the first and second radiator parts. The conductor part of the first radiator part electrically contacts the open turn of the third radiator part. The conductor part of the third radiator part electrically contacts the open turn of the second radiator part. At least one of the radiator parts is formed to be rotated about the longitudinal center axes of the helices of the first and second radiator parts.
In accordance with yet an added feature of the invention, the radiator parts are a plurality of first, second, and third radiator parts disposed such that respective longitudinal center axes of the helices of the first and second radiator parts are aligned. The respective longitudinal center axes of the rod and of the conductor part of the third radiator part extend parallel and/or inclined to the longitudinal center axes of the helices of the first and second radiator parts. A conductor part of one of the radiator parts electrically contacts an open turn of an adjoining conductor part of one of the radiator parts. At least one of the radiator parts is formed to be rotated about the longitudinal center axes of the helices of the radiator parts.
In accordance with yet an additional feature of the invention, the first radiator part has a first helix and a first plate part. The first helix has an end and a first longitudinal center axis. The plate part is disposed at the end and is disposed in a plane extending perpendicular and/or inclined to the longitudinal center axis of the first helix. The second radiator part has a second helix and a second plate part. The second helix has an end and a second longitudinal center axis. The plate part is disposed at the end of the second helix and is disposed in a plane extending perpendicular and/or inclined to the second longitudinal center axis.
In accordance with again another feature of the invention, the radiator parts are disposed with respect to one another such that the longitudinal center axes are aligned and the first plate part is opposite the second plate part at a predetermined distance. At least one of the radiator parts is formed to be rotated about the longitudinal center axes such that an area of coverage of the plate parts is changed with a respective degree of rotation.
In accordance with again a further feature of the invention, the plate parts are disc segments.
In accordance with again an added feature of the invention, the first radiator part has a first helix. The first helix has a first longitudinal center axis. The second radiator part has a second helix; the second helix has a second longitudinal center axis. The radiator parts are disposed with respect to one another such that the longitudinal center axes are aligned. The radiator parts overlap one another in a direction of the first and second longitudinal center axes and/or are opposite one another at a predetermined distance. At least one of the radiator parts is formed to be displaced along the longitudinal center axes such that an overlap area and/or the distance between the radiator parts is changed with a degree of displacement.
In accordance with again an additional feature of the invention, the first radiator part has a first helix and a first meander-shaped part. The first helix has a first longitudinal center axis. The second radiator part has a second helix and a second meander-shaped part. The second helix has a second longitudinal center axis. The radiator parts are disposed with respect to one another such that the longitudinal center axes are aligned and the first meander-shaped part contacts the second meander-shaped part. At least one of the radiator parts is formed to be rotated about the longitudinal center axes such that an inductance formed by the meander-shaped parts is changed with a degree of rotation.
In accordance with still another feature of the invention, at least one of the first and second meander-shaped parts is a radiating part.
In accordance with still a further feature of the invention, at least first and second radiator parts are applied to respective carriers, and the respective carriers are round and/or angular.
In accordance with still an added feature of the invention, the radiator parts are manufactured in MID technology.
In accordance with still an additional feature of the invention, the radiator parts are fixed with respect to one another after being set to a desired radiation pattern.
In accordance with a further feature of the invention, the helices have identical and/or different pitches, identical and/or different diameters, and equal and/or oppositely directed pitches.
With the objects of the invention in view, there is also provided a process for manufacturing tunable antennas, including the steps of constructing radiator parts for a respective antenna, coupling the parts to one another to permit the parts to at least one of rotate and displace with respect to one another, the couple being changed by at least one of rotation and displacement of the parts with respect to one another where a respective degree of at least one of rotation and displacement creates a corresponding change of a radiation pattern of the parts, measuring the radiation pattern of the parts; and adjusting the radiation pattern by at least one of rotating and displacing the parts with respect to one another to set a nominal radiation pattern of the respective antenna formed by the parts.
A process for manufacturing such a tunable antenna exhibits the steps of constructing the radiator parts for a respective antenna and disposing the radiator parts such that they are coupled to one another and can be rotated and/or displaced with respect to one another. For the respective antenna, an actual radiation pattern of the respective antenna is measured, and a radiation pattern of the respective antenna is adjusted by rotating and/or displacing the radiator parts with respect to one another in order to set a nominal radiation pattern of the respective antenna.
Accordingly, the process of the invention provides the possibility of readjusting, for example, the resonant frequencies of the antennas in a simple manner in the current manufacturing process by measuring the resonant frequency of a respective antenna and rotating and/or displacing the two radiator parts with respect to one another.
In particular, the process can be configured such that a first arbitrary number of antennas is manufactured by repeating the first two steps an arbitrary number of times and the actual radiation pattern of one or more of the first arbitrary number of manufactured antennas is measured. A second arbitrary number of antennas is manufactured by repeating the first two steps an arbitrary number of times, and a nominal radiation pattern of the antennas of the second arbitrary number is set based on a value that is derived based upon the measured actual radiation pattern of the one or more antennas of the first arbitrary number.
In accordance with a mode feature of the invention, a cap is placed on the antenna before and/or after adjusting the radiation pattern and/or setting the nominal radiation pattern.
In accordance with a concomitant mode of the invention, the parts of the antennas are mutually fixed before and/or after adjusting the radiation pattern and/or setting the nominal radiation pattern.
The invention provides, in a simple manner, the possibility of adjusting the antennas to a particular radiation pattern in the current manufacturing process.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a tunable antenna having separate radiator parts for tuning to a desired radiation pattern and a process for manufacturing the antenna, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.